We stayed at the Mariott as well! I really liked the hotel, especially how easy it was to get to the con center from the hotel itself. We had to park at a garage a few blocks away because my friend's truck wouldn't fit in the Mariott garage, but it was fine.
I have to agree about microwaves; we would eat out and have leftovers but couldn't save them because they would need to be reheated. I was also bummed with reception in the lower levels aka the meeting space but thats nothing that can be fixed. Awesome hotel otherwise!

Name: Amanda (WildSpice)
Hometown: Philly
This will be my 8th Otakon and my 3rd as Otakon staff; been going on and off since 2004.
Something interesting: I sometimes get to dress up as an astronaut character as part of my full time job!

Don't skip showering, hygiene, eating, sleeping, or drinking water.
Don't buy something you know you saw for less online.
Don't block a walkway, stand off to the side if you are taking a photo, talking, etc.
Don't keep bothering someone if they say "no" to a request you made (ex: taking a photo).